The present invention generally relates to constant velocity joints, and more particularly, relates to a venting mechanism for use in a constant velocity joint.
Constant velocity joints (CV joints) are common components in automotive vehicles. Typically constant velocity joints are used where transmission of a constant velocity rotary motion is desired or required. The common types of constant velocity joints are plunging tripod, fixed tripod, a plunging ball joint and a fixed ball joint. Constant velocity joints currently are used in front-wheel drive vehicles or rear-wheel drive vehicles and on propeller shafts found on rear-wheel drive, all-wheel drive and four-wheel drive vehicles. The plunging CV joints allow for axial movement during operation without the use of slip splines. Constant velocity joints are generally grease lubricated for life and sealed by a boot. Constant velocity joints are sealed in order to retain grease inside the joints while keeping contaminants and foreign matter, such as dirt and water, out of the joint. To achieve this protection, the constant velocity joint is usually enclosed at the open end of the outer race by a sealing boot made of a rubber, thermoplastic, silicone or other pliable material. The opposite end of the outer race is generally enclosed by a dome or cap, known as a grease cap in the case of a disk type joint. A mono block or integral stem and race design style does not use a grease cap. Instead it is sealed by the internal geometry of the outer race. The sealing and protection of the constant velocity joint is necessary because contamination of the inner chamber may cause internal damage to the joint. Furthermore, once the inner chamber of the constant velocity joint is lubricated, it is lubricated for life.
During operation, the constant velocity joint creates internal pressure in the inner chamber of the joint. These internal pressures increase as rotational speed of the constant velocity joint increases. These pressures have to be vented to the outer atmosphere in order to prevent pressure build up which occurs during operation of the joint. If the pressure build up is allowed to reach critical state, the boot may crack or have a blow out, thus losing sealability. Generally, a constant velocity joint is vented by placing a small hole generally in the center of the grease cap or at least one hole around the outer periphery of the outer race. These prior methods of venting the gas have some drawbacks because, if the constant velocity joint is in a static state and not rotating, the lubricating grease may migrate towards the venting hole and block or hinder its function of venting any internal gas pressure. This type of vent may also allow the infiltration of contaminants into the inner chamber of the constant velocity joint. Furthermore, the constant velocity joint has a tendency, after running for long periods of time, to create very high temperatures along with high pressures which are vented through the prior art vent holes. However, if the constant velocity joint is submerged or saturated in water or other contaminants, the water or other contaminants may, via a pressure differential, be propelled into the constant velocity joint, thus contaminating the grease and reducing the life of the constant velocity joint. Ingestion of water and other contaminants through the vent hole may reduce the life expectancy of the constant velocity joint.
Therefore, there is a need in the art for a constant velocity joint that will prevent the build up of internal gas pressure while eliminating the ingress of contaminants into the constant velocity joint. Furthermore, there is a need in the art for a vent that is low in cost, easy to manufacture and install on the constant velocity joint.
One object of the present invention is to provide an improved constant velocity joint.
Another object of the present invention is to provide a novel venting solution for a constant velocity joint.
Yet a further object of the present invention is to provide a vent for a constant velocity joint that is capable of releasing gas under pressure to the atmosphere.
Still a further object of the present invention is to provide a vent that will prevent the entrance of contaminants and liquids into the constant velocity joint.
Yet a further object of the present invention is to provide a constant velocity joint that will use a spring force in its venting mechanism to help seal the constant velocity joint under non-venting conditions.
To achieve the foregoing objects, a vent for a constant velocity joint for use in a vehicle is disclosed. The constant velocity joint vent includes a cover. The vent also includes a flapper valve secured to the cover. At least one post extends from the flapper valve and is secured to the cover. The vent also includes a bead extending from one side of the flapper valve that engages with the cover when the valve is in a closed position. The vent also includes a locator projection extending from the flapper valve near a mid point thereof.
One advantage of the present invention is that the constant velocity joint includes a vent that will allow for equalization of pressure inside the constant velocity joint to the outer atmosphere.
A further advantage of the present invention is that the constant velocity joint vent will stop the entry of contaminants into the constant velocity joint.
Still a further advantage of the present invention is that the constant velocity joint vent will be specifically designed to have a predetermined spring force that will allow a flapper valve of the vent to return to a sealing position.
Yet another advantage of the present invention is that the constant velocity joint vent will be easier to manufacture and reduce the cost of the constant velocity joint.